The present invention relates to apparatus and methods for dispensing flowable materials securely within containers and is particularly designed for use in dispensing granular or powdered materials. More particularly, the present invention relates to apparatus and methods for transferring flowable materials between containers in a manner which permits sealed isolation of the bulk storage container during both transferring and non-transferring usage. Although not necessarily limited thereto, the present invention is particularly useful for securely storing loose dry materials such as salt, pepper, sugar, flour and the like while permitting dispensing of those materials from a storage container to a receptacle container.
Various arrangements have been suggested in the prior art for bulk storage of flowable materials in a manner which permits rapid dispensing thereof into another container. For instance, plunger-type actuating pistons which seal the bulk container but permit gravity feed therethrough when the plunger piston is urged inwardly are shown in U.S. Pat. Nos. 3,042,085 by Morris, 3,061,152 by Safianoff et al, and 3,232,498 by Bennett. Such devices are an improvement for controlled dispensing purposes and generally accommodate some external securing of the bulk stored contents. However, they require the availability of special storage containers and are not well suited for attachment to existing containers such as those used for bulk shipment of products. In addition, such prior art devices require separate closure caps or the like if the dispensed materials are to be isolated from the environment after discharge from the bulk storage device. Further, telescoped tubular arrangements have been suggested for liquid dispensing nozzles such as in U.S. Pat. Nos. 1,946,314 by Desmond and 3,324,904 by Crothers. Such liquid dispensing nozzles employ the telescoped tubular members so that holes therethrough are exposed to permit liquid dispensing either by sliding the outer tubular member onto the inner member so that holes through both members align as with Desmond or by axially moving the outer member so as to expose holes into the inner member interior as with Crothers. Such devices are not well suited for dry material transfer nor are they adaptable for use with unmodified existing bulk storage containers. Additionally, such prior art devices require external exposure of the closure biasing springs and are subject to flow blockage when used for dry material transfer instead of liquid material transfer. Furthermore, as with the other prior art devices, Crothers and Desmond likewise require removal and replacement of a separate sealing cap in the receiving container in order to be effective for external isolation.
Despite the prior art developments, there has been a continuing need for devices which can be used in association with existing bulk storage containers so as to permit reliable transfer of flowable dry materials from those containers into other containers with secure external isolation of the storage container during material transfer as well as when not in use. Still further, there has been a continuing need for dispensing storage containers and receptacle containers which will cooperate to automatically seal both containers from the external environment while simply and reliably cooperating for establishing flow transfer therebetween in a manner which minimizes potential spillage loss during the transfer operation. The need for such devices is particularly evident for restaurant environments and the like where salt and pepper shakers, sugar condiments and the like must be regularly recharged from bulk storage containers.